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EXECUTIVE SUMMARY ~ Nonnative removal efforts within the middle Green River began in August 1997 and were completed in October 1998. Similar removal efforts were conducted from July 1997 to October 1998 in the lower Green River. Channel catfish and centrarchids were the primary focus of these removal efforts. The goal of this project was to implement fish control that effectively reduced negative interactions between nonnative fish and native fish in the Green River, Utah. At the ~ request of the recovery program, the final year of this project was not completed. Twenty river miles of the noddle Green River and ten river miles of the lower Green River were designated as removal reaches. The middle reach began at the confluence of the Duchesne River and continued dov~mstream The lower reach began at river mile 142 in Gray Canyon and r continued downstream to river mde 132. Baited fyke nets and shoreline electrofishing were the two methods employed to capture the target species. A total of 15,695.25 fyke net hours and 52.06 hours of electrofishing were expended in the middle Green River. In the lower Green River, approximately 7,019 fyke net hours and 41 electrofishing hours were expended. i A total of 35,311 (93$.47 kg) nonnative fish were removed by both fyke netting and electrofishing during 1997 and 1998 in the middle Green River. Ninety percent of nonnative fish captures were channel catfish and they comprised 61 % of the captured total fish community biomass. Smallmouth bass comprised 1 % of the total nonnative fish catch and 4.4% of the total fish community. In the middle Green River, electxofishing was found to be the most effective method ~ for capturing centrarchids. Centrarchids had the second highest catch rates, following channel catfish during 1997 electrofishing. Channel catfish catch rates were highest during the September trips for both fyke netting and electrofishing in both years of sampling. Smallmouth bass catch rates increased steadily throughout the sampling season in 1997 and were highest in August 1998. Baited fyke nets primanly collected small channel catfish. Catch rates of small channel catfish ~ collected in fyke nets significantly dropped between the two sampling years in the middle Green River. During 1997 and 1998, a total of 9,463 nonnative fish were removed from the lower Green River by fyke netting and electrofishing. Approximately 96% of nonnative fish captures were channel ~ catfish which comprised 84.1 % of the captured total fish community. Ninety-seven percent of all baited Tyke net catches were channel catfish. As in the middle Green River, baited fyke nets collected primarily small channel catfish. Large channel catfish were Est abundant during the October eleffirofishing trip. In the lower Green River, smallmouth bass were not present and channel catfish were the most common species captured by electrofishing (76%). Flannel~uth R sucker were the second most abundant fish collected after channel catfish by electrofislung. During 1998, medium and large channel catfish catch rates increased between trips, and catch rates for medium and combined size classes combined of channel catfish significantly increased between years. . While electrofishing tends to collect a wider range of size classes, the small size class of channel catfish were still the most abundant in the catch of this project. This indicates that the middle and lower Green River may provide nursery habitats for the smaller immature channel catfish. Thus, the methods employed during this project were specifically designed and refined to target small ~ vui